Heavy duty vehicle applications are constantly looking for alternative suspension configurations that provide improved ride characteristics when compared with conventional mechanical suspensions, such as a leaf spring suspension for example. Any alternative suspension must also maintain or provide improved handling performance as compared to the mechanical suspension.
One type of alternative suspension is an air suspension that utilizes air springs to provide a softer ride. One type of air suspension, referred to as a multi-link air suspension, offers improved handling performance as compared to traditional leaf spring suspensions. Multi-link air suspensions include longitudinally extending control link arms that are mounted to vehicle and axle structures with bushings.
One disadvantage with such an air suspension is that a sway bar is required to provide needed auxiliary roll stiffness. The sway bar extends in a lateral direction and is typically connected to control link arms that are laterally opposed from each other. The addition of a sway bar to the suspension significantly increases the overall weight of the suspension, making it difficult for this type of suspension to be competitive. Additionally, future emission and braking regulations may make this type of air suspension even more unattractive due to the additional weight of the sway bar.
Thus, there is a need for an improved linkage system that is configured to provide desired bushing characteristics, as well as auxiliary roll stiffness, such that the need for a sway bar in such a suspension is eliminated.